Discovery of a new Y dwarf: WISE J030449.03−270508.3

• Published in: Monthly notices of the Royal Astronomical Society 2014-10, Vol.444 (2), p.1931-1939
• Main Authors: Pinfield, D. J., Gromadzki, M., Leggett, S. K., Gomes, J., Lodieu, N., Kurtev, R., Day-Jones, A. C., Ruiz, M. T., Cook, N. J., Morley, C. V., Marley, M. S., Marocco, F., Smart, R. L., Jones, H. R. A., Lucas, P. W., Beletsky, Y., Ivanov, V. D., Burningham, B., Jenkins, J. S., Cardoso, C., Frith, J., Clarke, J. R. A., Gálvez-Ortiz, M. C., Zhang, Z.
• Format: Article
• Language: English
• Subjects: Discs; Dwarf stars; Flux; Infrared; Mathematical models; Metallicity; Space telescopes; Spectra; Spectrum analysis; Temperature; Trends; Visual; Wide-field Infrared Survey Explorer
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stu1540

We present a new Y dwarf, WISE J030449.03−270508.3, confirmed from a candidate sample designed to pick out low-temperature objects from the Wide-field Infrared Survey Explorer (WISE) data base. The new object is typed Y0pec following a visual comparison with spectral standards, and lies at a likely distance of 10–17 pc. Its tangential velocity suggests thin disc membership, but it shows some spectral characteristics that suggest that it may be metal poor and/or older than previously identified Y0 dwarfs. Based on trends seen for warmer late-type T dwarfs, the Y-band flux peak morphology is indicative of sub-solar metallicity, and the enhanced red wing of the J-band flux peak offers evidence for high gravity and/or low metallicity (with associated model trends suggesting an age closer to ∼10 Gyr and mass in the range 0.02–0.03 M⊙). This object may thus be extending the population parameter space of the known Y0 dwarfs.